Graphical representation of expression (2), in which I(X) shows the intensity distribution of the diffraction pattern given by the sinusoidal transmission grating, of which the spacial frequency is f0 and the width is W.

The reconstructed spectrum. This is photographed by panchromatic emulsion (ASA 100) with almost 2 h exposure. Two spectral lines are seen on both sides of the central dark part which corresponds to the zero-order spectrum.